Heat Flux Boundary Condition
Hi, I am trying to impose a constant heat flux BC to the common face of two metal blocks. But comsol does not allow me to select that face for this type of BC. In fact, only outer boundaries are...
View ArticleCapacitance matrix evaluation (electrostatics)
Hello everyone, i have a question about the capacitance calculation method. In comosl example "Capacitance matrix", it explains that the electrostatics model use the Charge volateg relationship (Q = C*...
View Articleinterface to be used in studying electrochemical reactions
what interface should i use in Comsol 4.3b if i want to study species transport inside the electrolyte,ion transport including convection,diffusion and migration and electrodic reactions represented by...
View ArticleMapped Coordinate System for L-Shape
Hello, I would like to simulate the deformation of an L-Shape made of carbon fibers. In the beginning the L has an angle of 90 degrees but after it is cured in the oven, there is a spring-in effect,...
View Articlemoving inner boundary by defining prescribed displacement
Hello everyone This may have an obvious answer but I am a bit new with Comsol so I am playing around with various interfaces, particulary the ale interface. I am trying to deform an inner boundary by...
View ArticleHow to use compressible gas flow .
Hi I am trying to find a module for doing the analysis of a gas flow in a little 2-d chamber where I am using a compressible gas at a predefined pressure from a tank ranging from 3-6 psi-g at the inlet...
View Articlehollow core photonic crystal fiber using comsol multiphysics.
dear collegues, Iam simulating HC-PCF using comsol based on hybrid modewaves operated at free sace wavelength 1500nm in IR region. Iam unable to confine light through hollow core. please give me a...
View ArticleRF frequency domain scattering electric field module- normalization of...
I am uncertain if I am incorrect in my assumption, so I have come here hoping someone can clarify for me. emw.Ex -displays the scattered electric field emw.Ebx -is initial background electric field...
View Articleparameter sweep error when loading a geometry
I am applying a load to the top of the geometry shown while the bottom is fixed but i keep getting an empty parameter sweep error can u help me??
View ArticleConvergence problem with Open Boundary condition - No viscous stress
Hi, I'm modeling fluid flow through a 2D porous media using Darcy's Law. I intend to estimate fluid flux values across the top boundary of model, however,my desired outputs will be one in which the...
View ArticleCouple diffusion and convection
Hi, I have a packed bed with spherical elements from which material is being extracted. I would like to know the concentration profile in the particles and in the axial direction of the packed bed. I...
View Articlepoint load at arbitrary points
I am working on a cylindrical model. I need to apply load at points.Not the predetermined points but other points too.suggestions please
View Articlemodifying model variable after each time step
Hi, I have a coupled system of PDEs. I want to modify the variables after each time step where it is calculated. In fact any time that comsol computes the variable I want to ask it to enforce some...
View ArticleAdding points and lines to 3D models with parametric surfaces
Hi all, I was wondering if there is a way to add a point or line to a model in which I have a 3D block with the top surface replaced by a parametric surface derived from a DEM (digital elevation...
View ArticleElectric potential and current density analysis
Dear friends, I analyzed a model using Time-dependent solver and for the time: range (0, 0.016,1). The model is consisted of different layers with different conductivity and permittivity and a Terminal...
View ArticleMesh resolution investigation
Hello I want to check my mesh convergence. I use "user-controlled mesh". under "free trianglular" I define 3 sizes .one for my domain and two for the boundaries. my question is that in order to test...
View Articlehow to assign conductivity to fluid flow in a microchannel preconcentration...
I am modeling a solution phase preconcentration in microchannel. My system has two inlets and one outlet. From inlet1, buffer (10mM) containing a negatively charged dye is supplied and from inlet2 same...
View Article3D waveguide in time domain.
Hi, I am trying to model a 3D waveguide and I am using a Gaussian pulse and I need to define an excitation port for the model. I can do this in 2D, but it seems in 3D it is really difficult as far as I...
View Articlehow to apply two phase voltage in an Piezo Divice
Hi, I modeled a piezo actuator driven by two phase voltage that one is 90-degree behind, that is sin(wt) and cos(wt). Now I'm doing a frequency domain study，BUT how could I applied the voltage? I've...
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